Currently, as medical imaging diagnosis apparatuses such as CT (Computed Tomography) scanners, MRI (Magnetic Resonance Imaging) apparatuses, PET (Positron Emission Tomography) apparatuses have been known. While using such imaging apparatuses, a chemical liquid such as a contrast medium or a saline (hereinafter, simply referred to as ‘a chemical liquid’) is often injected into the patient's body.
While injecting the chemical liquid, sometimes a tip of an injection needle may come off a blood vessel of the patient and the chemical liquid is leaked out of the blood vessel (this is also called as ‘extravascular leak’). In Patent Document 1 for example, a technology for determining if there is an extravascular leak or not has been disclosed. In the technology for determining the extravascular leak, infrared rays are irradiated to a portion of the patient's body by using a light-emitting diode (LED) and light reflected is received by a phototransistor. From the intensity of the light reflected, it is possible to determine if there is an extravascular leak or not.